This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This natural history study is necessary to understand glycogen storage disease as people diagnosed with this disease age. Since the treatment for glycogen storage disease was first implemented approximately 30 years ago, the first generation of patients is now surviving into adulthood. It is important to follow these patients and assess the status of the population. While clinical advances have resulted in amelioration of the biochemical abnormalities in the glycogen storage diseases, long-term complications continue to occur. This study will attempt to understand the role of metabolic control on the development of complications. In particular, the effect of metabolic control on hepatic adenoma formation, hepatocellular carcinoma development, renal complications, and anemia will be assessed.